Security: Joomla-based Website

I used [url removed, login to view] last year to find someone to set up a website for me. I was successful in finding someone but haven't been able to contact him to fix this security issue I am now having. (He lives in the UK) I'm hoping someone from [url removed, login to view] will again be able to help me.

He set up the site using Joomla, which I had to make myself familiar with. I think we've been hacked (I'm pretty sure of it, actually) and now I don't know what to do. I can't access the front-end or the back-end of the site. At first, I just wasn't able to login, I kept getting a username/password error. A few hours later and the site was completely inaccessible and was attacking the PCs of anyone that tried to access it. The only thing I could think of to do so no one's PC would get infected was to go to my hosting site cpanel & password protect the entire public_html directory. It's been over 24 hours since this happened and I need to get my site back up & running ASAP.

I prefer someone that lives in the U.S. and has extensive Joomla knowledge and can actually fix this. I've scoured the Joomla forums and I think I need to update my Joomla version, but since I can't even access the Joomla cPanel, how can I do this? From my web hosting cPanel? That's where I get lost.

Please contact me at your earliest.

This is just a fan site for a music artist. We don't have much money and honestly, this doesn't seem like something that would take hours to do. Once you get us back up and running, we will be able to install security updates from Joomla extensions that will prevent this from happening in the future. We really prefer someone who has a RATING.